The present invention relates to a method and apparatus for making notebooks or pads whose leaves are held together by spiral binders consisting of metallic or synthetic plastic material. More particularly, the invention relates to improvements in a method and apparatus for the mass production of such pads.
Presently known automatic apparatus for the manufacture of note books or pads whose leaves or sheets are held together by spiral binders process a continuous web of paper or like sheet material. The web is withdrawn from a bobbin and is caused to pass through an imprinting mechanism so that it can be converted into leaves of ruled pads. Both marginal portions of the running web are provided with rows of performations by means of rotary punching tools and the web is thereupon halved, i.e., it is severed midway between its perforated marginal portions. In the next step, the resulting narrower webs are severed crosswise so that each thereof yields a row of discrete sheets or leaves having a size corresponding to that of the leaves in a finished pad. Successive sheets of each row are caused to overlap each other, i.e., to form scalloped streams, and the two rows of overlapping sheets are moved apart, i.e., transversely to the longitudinal direction of the rows. In the next step, each row is converted into discrete pads each of which contains a predetermined number of sheets or leaves. The two rows of pads are thereupon advanced in stepwise fashion along discrete paths wherein the perforations of successive pads are aligned for introduction of binders. The ends of such binders are trimmed and deformed.
The just described automatic apparatus are suitable for the mass production of pads with leaves having a predetermined size. The output of such apparatus is limited due to the relatively slow operation of imprinting mechanism, i.e., the output is lower than that which is warranted by the intervals required for other stages of the processing and assembling operation.
It is also known to manufacture spiral binder pads by resorting to semiautomatic apparatus. In such apparatus, stacks of imprinted (ruled) sheets are inserted by hand, and the length of each sheet equals the combined width of two finished pads. The stacks are transported stepwise during travel along a first section of their path, and each stack is converted into several smaller stacks whose sheets are perforated prior to reassembly of smaller stacks into larger stacks. The perforating step involves applying a row of perforations to one edge portion of each smaller stack, namely to an edge portion which extends in parallelism with the direction of transport of smaller stacks. The direction of reassembled (larger) stacks is thereupon changed by 90 degrees, and each stack is halved to yield a pair of pads. The pads of each pair are moved apart so that the width of the gap between two neighboring pads is a multiple of the distance between a pair of neighboring perforations. A spiral is introduced into the perforations of each pair of spaced-apart pads, and the spiral is trimmed between the respective pads to yield two binders, one for each pad. The intermediate portion of each spiral is discarded.
The output of the just described semiautomatic apparatus is limited due to relatively low speed of the punching mechanism. Proposals to employ sheets whose length equals three times the width of a pad have met with limited success because the utilization of longer sheets necessitates a lengthening of intervals between successive stepwise advances of the sheets and pads.